Ring and ball mill



26, H. v. SPAULDING 2,253,819

RING AND BALL MILL Filed April 26, 1938 5 Sheets-Sheet 1 Jyt/ INVENTOR. Harold V Spau/ding A g- 1941- H. v. SPAULDING 2,253,819

RING AND BALL MILL Filed April 26, 1938 I 5 Sheets-Sheet 2 I l l2 3 p I /2P) /4 1 2 2 64 Ix 2: 2o, 1/"

m /4 (J 70k '3 201, 6 2 5.5

INVENTOR. I Harold V.$paulding BY 5 v ATTORNEY.

Aug. 26, 1941; H. v. SPAULDING 2,253,319

RING AND BALL MILL Filed April 26, 1938 5 Sheets-Sheet ,3

iii-{71 x 11/ INVENTOR. Harold M Spaulding v ATTORNEY.

Aug. 26, 1941. H. v. SPAULDING' 2,253,319

' RING AND BALL MILL Filed April 26, 1958 5 Sheets-She 4 INVENTOR.

Harold MSpau/dinj ATTORNEY.

Patented Aug. 26, 1941 UNITED STATES PATENT OFFICE RING AND mu. MILL Harold v. Spamming. Seattle, Wash. Application April 2c, 1938, Serial No. 204,326

' cl. aa-4s) balls and ring for regrinding, until fine enough to 9Claims.

This invention relates to grinding and pulverizing machinery in general, and particularly to ring and ball mills adapted to grind and pulverize the ores of precious metals, rock or other materials. r

Ring and ball mills are favorably known for their grinding and pulverizing ability, but heretofore have been heavy, cumbersome and expensive, and intended for installation in locations where the heavy parts may be transported by railway cars, trucks or sturdy wagons.

Various means have been devised to impart the driving force to the balls without undue wear in the mechanism employed, but, prior to my invention, because of the very nature of the problem, the excessive wear of these parts has very objectionable and expensive.

Various modifications and improvements in design have been evolved to provide a really efi'ective and reliable control of the finenessv of a the ground material discharged from pulverizing machinery, but prior to my invention where a specified fineness was demanded, external classifiers have been-required.

In the device of my invention the construction is such that none of the parts of the mill in the sizes'used in the initial stages of development of mines in relatively inaccessible locations, are

' so heavy that they cannot be transported by pack animals, and in the smaller sizes'by men packers.

The grinding balls are rolled around the inner surface of the grinding ring by means of an in:- terior rotor element through the. intermediacy of resiliently mounted driving shoes. The arrangement is such that the rotor, balls and grinding ring constitute a planetary system, wherein the ring is fixed and the balls are driven by friction contact with the driving shoes 01' the rotor, which may be motivated by any suitable source of power. This construction permits the use of higher rotor speeds, simplified construction, little wear and a great saving in weight for a given capacity;'and provides other advantages in connection with thefgrinding operation itself.

One of said advantages is that this construction permits the use of water as the medium in which the grinding or pulverizing'takes place, .thus enabling water to be used to convey the coarse material between the ballsand ring for grinding, and then to carry the pulverized material of the required fineness through an hydraulic classifier located at a higher level within the mill .itself, and to re-convey the less finely ground and rejected pulverized material between said leave the mill by way of said classifier.

An object of the invention is to provide a ring and ball mill for pulverizing various materials, that is comprised of a plurality of parts that may be conveyed by pack animals and men into places that are inaccessible by rail or road.

Another object is to provide ag'rinding mill of the kind described, in which the ring is fixed and the balls are driven by friction contact means carried by an interior rotorelement.

An additional object is to provide a'device of the kind described wherein the grinding or pulverizing may be done in a water or other liquid medium without undue wear of the grinding parts. I 7

A further object is to provide means for circulating water or other liquid through a mill of the kind described to form a feed and regrind circuit for conveying the coarse material to the grinding elements, and the ground material away from said grinding elements.

A still further object is to provide adjustable hydraulic classifying means within the mill, that V permits pulverized material of the desired fineness to be discharged promptly therefrom, but which returns the less finely pulverized material to said regrind circuit for further grinding.

A still further object is to provide means in a mill of the kind described for continuously sampling the dischargedmateri-al.

Other objects and advantages will be apparent to those skilled in the art from the following detailed description of a preferred form of the invention, which consists of certain parts and combination of parts, hereinafter described, i1- lustrated in the accompanying drawings and embraced in the appended claims. In the drawings: Y

Figure l is a right side elevation of the mill showingone means 'of'driving the rotor, and

other features of its construction, with the water supply pipe removed;-

Fig. 2 is a front composite sectional elevation taken medially through the body of the mill, in-

assembly with a sectional elevation through the top and bottom shoes, taken on broken line 4-4 of Fig. 3;

Fig. 5 is aplan view of the mechanism remaining after removing the separable top portion of the housing and appended parts, with the drive tube, tension rod and intake in section, as taken on broken line 5-5 of Fig. 2;

Fig. 6 is a plan sectional view through the base of the mill taken on broken line 6-8 of Fig. 2, showing the feed and regrind flow channel, and flow inlet at the .center of the main flow impeller;

Fig 7 is a fragmentary medial sectional elevation of the left side of the top section of the mill housing, showing the support for the adjustable classifier with the continuous sampler in position, and to a larger scale than that of Fig. 2;

Fig. 8 is a sectional-elevation taken on broken line 8-8 of Fig. 7; and

Fig. 9'is a sectional plan view taken on broken line 9-9 of Fig. 7.

Like referencenumerals are used to indicate like parts throughout the drawings, wherein the numeral l0 indicates the base, It the intermediate and I2 the top separable sections of the housing respectively, which are secured .together by means of a plurality of bolts and nuts l3 and 13', shown best in Fig.1. Gasket rings I4 and ll of rubber or other suitablematerial make the joints water tight, as shown in Fig. 2. ;The base section is provided with arms Id and the intermediate section with arms Ila, thro which holes are provided to receive rod ii to form a convenient hinge connection for opening the mill, as hereinafter explained. I

The grinding ring may be comprised of two separable sections to facilitate their transportation and renewal, and to permit the aforesaid opening of the mill. Lower section 1611 of the. grinding ring articulates with the base section,

and-upper section lfibj with the intermediate sec-- tion of the housing.

Grinding balls I! preferably are of such size and number that they make maximum use of the interior grinding surface of the ring sections, as

indicated in Figs. 2 and 3. They are motivated by means of the rotor member l8 through the intermediacy of shoes l3, each of which is provided with top and bottom grooves that engage ribs 201' of top disk 2llt and bottom disk 20!) of said rotor-member. Said shoes are positioned vertically between said disks by means of rubber liners 2|, that provide flanges 2|! adjacent ribs 201. By means of this arrangement it will be seen that each shoe is free to slide radially in and out between the rotor disks, and that the driving forceis transmitted from ribs 20r to the shoes through flanges 2 I f of rubber liners 2|- By referring to Fig. 2, it will be seen that the outer face of each shoe iscurved to fit snugly against the surface of the grinding balls. In order to provide uninterrupted contact with said balls, each shoe may be provided with a tongue l9t' which articulates with a groove I90 in the adjoining shoe, as illustrated best in Fig. 4.

Bottom disk 20b of the rotor may be made integral with square core member 22, which preferably is provided at its upper end with a drive flange 22d, having upwardly disposed lugs 22c, and an axial cylindrical guide projection "221). A guide shaft 20s projects downwardly from said bottom disk and has its journal end positioned laterally in bottom guide bearing 23, formed in the base section and provided preferably with a rubber sleeve 24. Flange 20f is aflixed to the 2,258,819 I disks and articulated driving guide shaft adjacent the top of said bearing sleeve to centrifuge the crushed and ground material away from the top of the bearing. The guide bearing is "1ubricated by the water within the mill, a small amount of which works downwardly between the shaft journal and rubber bearing liner, and is discharged through drain pipe 23;) in which a valve, not shown, may be installed to regulate the flow.

Top disk 2llt has apertures that fit snugly over said projection and lugs, which align the ribs of the two disks and provide a simple and eifective driving connection for the rotor elements.

With the top disk removed, compression springs 25 and strut elements 26 may be placedin position between opposite driving shoes. Referring particularly to Fig. 3, it will be seen that each shoe is provided with projections l3p that-posi tion pads of rubber l9r, which in turn engage either a cupped washer I910 adapted to receive the thrust from, and to position one end of, a spring or the cupped end of a strut. Each strut has a large transverse aperture through which the spring of the adjacent shoe passes. Said aperture is so proportioned that there is no interference between the strut and spring during the operationof the mill, even after the parts have become worn to the extent that they must be replaced.

After articulating the shoes, struts and springs, and with the mill opened as indicated in Fig. 3, the grinding balls may be placed in position between the lower grinding ring section and shoes, thus compressing the springs to their several operating positions. With the upper section of the grindingv ring in position therein, the intermediate section of the housingnext 'may be closed, and secured by means of bolts and nuts l3, The assembled housing units then will appear as shown in Fig. 5.

Again referring to Fig. 2, it will be seen that funnel element 21 has a plurality of lugs 2111, which bear upon funnel support lugs l2a of top v section l2. Aligned holes in said lugs are provided to receive bolts and nuts 21!), used to removably secure said element to the top section, whichdn turn is secured to the mid section by I bolts and nuts I3.

The top section also supports a bearing assembly comprising an H-frame 28a secured to' the top flange of said section by means of studs and nuts 28b, and a yoke 280 secured to the tops of the side elements of the -H-frame by means of studs and nuts 28d. The H-frame provides guide I bearing 28a and the yoke a second guide bearing 28c ada'ptedto rotatively position tubular shaft 29, the lower end of which'flts over guide projection 22p, and is provided with'a flange 2911 having apertures for lugs 22c. This engagement of said flange and lugs provides a separable driving connection between shaft 29 and rotor member I; the same being maintained during the operation of the mill by means of tension rod 30 and flanged head piece 3|. A grooved drive pulley 32 may be fixedly secured to the tubular shaft between bearings 28a and 230';

Yoke 230 also supports the weight of the rotating parts of the'mill through the intermediacy of ing for shaft 203.

ball thrust bearing 33, bearing closure hood 33h,

nut 33w, tension rod 30 and head piecejl, hence bearing 23 in the base section is relieved of any vertical load and'functions only as a guide bear- Pulp classifier 34 comprises a body portion 34a providing an annular channel having a sloping on the upper ends of bearings I Id and 28d, re-f bottom to facilitate discharging the pulp into spout portion 34b, fixedly secured to an adjustable slide 35 so the pulp may discharge into a pulp well 36, which is formed ,by an extension |2b of top section I! and said adjustable slide, together with partition blocks 31, secured to the walls of said extension by cap screws 38, and other parts used to form a water tight seal between said partition blocks and the adjustable slide, as shown best in Figs. '7, 8 and 9. v

By means of this feature of the invention, the classifier may be adjusted to different-heights to control the fineness of the pulp, as hereinafter more fully explained.

In order to permit the adjustment of slide 35 and still provide a water tight partition between the interior of top section I! and pulp well 36.

I prefer to employ guide strips 39, adjustably secured to the partition blocks by means of bolts and nuts 39a, recessed seal strips 40 and adjustment strips 4|, secured to the bottom of the pulp well by cap screws 2, together with interior rubber seal strips 43,- exterior rubber seal strips 44 and bottom rubber seal strips 45.

Attached to slide 35 is a strip 350 of flexible material, such as bronze, which may be coiled within a guard 46, also secured to the bottom of the pulp well by cap screws 12. The adjustment of the several parts may be such that slide 35 and strip 35a may be raised or lowered a little at a time while the mill is in operation until the pulp discharged is of the required fineness,

and then looked in that position by means of screw 38a.

When the slide is raised, strip 350. is uncoiled and covers the space between seal strips 45 and the bottom of the slide. When necessary to maintain a tight seal, blocks, not shown, of the spectively, to support the weight of the countershaft assembly and of the counter-shaft portion of the belting.

'I'he belt between the large crowned pulley 50 and a small crowned pulley on the high speed power means, not shown. usually is a quarterturn flat rubberized belt. Because of the short center to center distance between shafts 29 and 49, I prefer to use multiple strands of endless rubberiz'ed belting 52 that fit 'in the V-groove's in small pulley BI and large drive pulley 32.

By means of this arrangement of pulleys and belting. I provide the mill with a self-contained speed reducing element. so power means operating at say 1750 revolutions per minute (R. P. M.) may be connected to the mill unit with a single fiat belt to drive the rotor assembly at say 200 R. P. M. For the proportions herein illustrated, a ball will complete of a traverse of the ring, and will rotate approximately revolutions about its own axis for each revolution of the rotor, hence with the combination of my speed reducing element and the planetary system relation between rotor, ball and grinding ring, it will be apparent that with the power means operating at 1750 B. P. M., a ball will complete approximately 200'=75 traverses of the grinding ring sections perminute, and will rotate about its own same thickness as the slide may be used below the slide to force the strip against the interior rubber seal strips. tight when only water,-or pulp of the required fineness, can seep through the partition elements.

When the slide is lowered, strip a again coi within guard 46 because of the resiliency of the previously coiled metal. Screwiilb may be used to hold the slide and appended parts when raised beyond the range of screw 38a.

To providefor continuous or periodic checks of the pulp being discharged from-the pulp well through spout 38a of the top section, a small basin 4! is so secured to spout34b that it receives a proportional part of the pulp discharged into the pulp well, and delivers it to a sampling well 48 by means of discharge pipe "a. The pulp sample is discharged from the sampling well through sampler spout 48a, from which it may be conveyed through a suitable pipe not shown, directly to the laboratory or back into the main pulp stream, as'desiredby the operator. The fiow from the sampling well should be continuo s while the mill is operating to prevent the pulp edly secured to the top H-frame of the mill, as

shown in Fig. 1.

A large crowned pulley 50 and a small multiplegrooved pulley 5| are fixedly secured to the coun- The sealing is sufllciently axis approximately %X200=375 R. P. M.

Because the-drive between the rotor element shoes and .the balls depends upon frictional contact only, there is some slip, but even this slip is utilized in pulverizing the small percentage of solids that pass between said shoes and balls, and which both provide a grit to reduce slipping and at the same time permit a certain amount bf slip as they are broken into smaller minute particles by the grinding operation.-

The mill is filled with water entering the bottom section under pressure through piping 53,

in which valve 54 may be placed to obtain the I optimum rate of discharge from the classifier for a given .fineness of the. pulp. The water is I forced to circulate through the machine by means of a plurality of main. centrifugal impeller arms 55 fixedly secured to the lower side of bottom disk 20b of the rotor, assisted by secondary impeller arms 56 fixedly attached to the top side of flange 2911. A shroud ring55'a is afiixed to the lower edges of arms 55 to increase their strength and efi'ectiveness.

The material, such as ore, to be pulverized after having been crushed to pass through a ter shaft so the lower ends of their hubs bear screen of given mesh, not shown, may be fed through trough 51 into hopper 58, from which it drops through intake tube 59 into flow passage 60 that may be formed by cored additions HR: and [0k to the mid and bottom castings respectively, as shown clearly in Figs. 1, 2, 3 and 6.

As the incoming material enters the flow passage of the operating mill, it is carried by the current of circulating water-upwardly through intake ring 6| in the bottom of the mill, from which itis centrifuged outwardly by impeller arms 55 through the openings between the balls, there to be ground between the balls and grinding ring sections. Heavy particles of the 'material that tend to drop downwardly are forced upwardly again between the balls and ring sections by the current until ground fine enough to be carried along by the circulating water flowing at relatively high velocity above the rotor into chamber 4- I plate lip of the top section into an upper cham,-

ber I3, and thence from the top rim of funnel 21.

toward the rim of annular pulp classifier ila.

only those portions of the ground particles that are small enough to be carried inwardly and upwardly by the discharge fiow of water from the top-rim of thefunnel over the rim of and into the classifier, are discharged as pulp through spout 341) into pulp well 36, and from there through discharge opening "a into a tube or trough, not shown, used to convey the pulp away from the mill. It will be apparent to those skilled in this art, that by increasing the height of the adjustable clazsifier, as hereinbefore explained, the fineness of the discharged pulp will be increased; and by decreasing its height with reference to the top rim of the funnel element, the fineness of the pulp will-be decreased.

invention within the scope of the appended claims.

and material between said ball'sand through said That portion of the fines passing overthe I of the funnel element comprising particles that are too large and heavy to be carried inwardly and upwardly by the relatively slowly moving stream of water into the classifier, sinks and is drawn downwardly to the lower end of said funnel element, where it is centrifuged by impeller arms 58 into chamber 62, and from there it combines with the particles that are too heavy to pass upwardly through the opening in partition plate i212, but are drawn instead'into the mouth of regrind duct 64 and thence into fiow passage til by the water circulated by the primary and secondary impeller arms to be re-ground between the balls and ring sections. The foregoing regrinding operation obviously is repeated until the A rubber jacketed plug 55 is forced into a drain a ring element having an inner grinding surface,

opening in base section Ill by tension spring 86, through the intermediacy of linkage elements 81a, 61b and 68, the last of which also serves as an operating lever. By pulling lever 88 to the left, as seen in Fig. 2, plug 55 may be withdrawn from said opening, which is large enough to permit the mill to be drained quickly into a pipe or trough, not shown, before the solids have a chance to settle. l

After emptying the mill and-removing nuts l3 and tension rod 30, the hinge connectionyprovidedby arms Ilia and Ila. and rod l5, may be used to support the upper portion of the mill as the same is opened at the dividing plane indicated by broken line 3-3 of Fig. 2 for washing the interior, inspection, repairs or replacing worn parts.

A 30-inch diameter mill, constructed as herein illustrated and described, weighs less than 1500 pounds, yet none of the parts comprising the assembly weigh more than 300 pounds, which is well within the usual loadlimit for pack animals. The capacity of a mill of this size is from to V tons of pulp of 100 mesh fineness in 24 hours,

with a power requirement of 7-horse-power.

While I have illustrated and described a preferred form of my improved ring and ball mill, it

out departing from the purpose and intent of the housing. ducts and aperture, conduit means for conveying a fiow of said liquid into said housing, an uprightlfunnel element secured within said housing above said rotor means, an hydraulic classifier comprising a fiow discharge channel, means for supporting and adjusting the position of saidclassifier with reference to the top rim of said funnel element, and secondary impeller means adjacent the lower end of said funnel element.

2. In a mill for pulverizin'g ore and other materials, the combination of an upright housing comprising a grinding compartment and an adjacent pulp well separated by a partition, a liquid in said grinding compartment, grinding means in said compartment and submerged in said liquid, conduit means for conveying a flow of liquid into said housing, an hydraulic classifier comprising a discharge conduit through and fixedly secured to said partition and supporting open-top channel means for receiving thedischarge flow of said liquid and the pulverized said materials carried upwardly thereby, and sampling means secured to the end of said discharge conduit for diverting therefrom a proportional part of said discharge fiow.

3. In a ring'and ball mill, the combination of a plurality of balls disposed successively along ably engaging the guide means of said rotor silient means reacting between each said pair of shoes independently of said rotor for forcing said shoes outwardly into driving engagement with said balls.

5. In a ring and ball mill, the combination of a ring element having an inner grinding surface, a plurality of balls disposed successively along the grinding surface of said ring element, a rotor frame disposed medially of said balls, a plurality of pairs of diametrically opposite rotor shoes slidable radially in said rotor frame, means for articulating the adjacent ends of said shoes adapted to provide uninterrupted contact between said shoes and said balls, and resilient means reacting between each said pair of shoes independently of said rotor for forcing said shoes into driving engagement with said balls.

6. In a pulverizing mill, the combination of a stationary upright housing containing a liquid, grinding means submerged in said liquid, conduit means for conveying a fiow of said liquid and the material to be pulverized into said housing and through said grinding means, an upright v funnel element fixedly secured within said housing above said grinding means and immersed in said liquid with its larger diameter rim near the upper surface thereof,- an hydraulic classifier comprising an open-top flow discharg channel, means for adjustably supporting said classifier immersed in the relatively quiet zone of said liquid above said funnel and'with reference to the top rim thereof, and impeller means for causing said liquid to circulate downwardly through the interior and upwardly past the exterior of said funnel.

7. Ina liquid immersed ring and ball mill, the combination of a stationary upright housing comprising a bottom having an annular inclined interior surface sloping upwardly from a medial aperture through which a liquid and the material to be ground may flow into said mill, a horizontally disposed grinding ring comprising an interior grinding surface and fixedly secured to saidhousing with the lower edgeiof said grinding surface adjacent the outer edge of said annular inclined interior surface, a plurality of balls so disposed against saidring as to provide a plurality of space intervals between the'surfaces of said balls and the grinding surface of said ring, medially disposed rotor means adapted to force said balls to roll along the grinding surface of said ring, centrifugal impeller means fixedly secured to said rotor means above the medial aperture in the bottom of said housing for forcing said fluid and material to flow upwardly thorugh said aperture then outwardly over said inclined interior surface and thence upwardly through the space intervals between said balls and ring when said rotor means is revolving.

8. In a ring and ball mill adapted togrind and regrind the material fed into it until of a predetermined fineness, the combination of a stationary upright housing having side and medial bottom apertures, a conduit fixedly secured to said housing and connecting saidside and bottom apertures, means for feeding th material to be ground into said conduit, a fluid in said housing and conduit, a horizontally disposed ring comprising an inner grinding surface and fixedly secured within said housing, a plurality of balls disposed successively along the grinding surface of said ring, medially disposed rotor means adapted to force said balls to roll along the grinding surface of said ring, centrifugal impeller means fixedly secured to said rotor means above the medial bottom aperture in said housing and adapted to cause said liquid to circulate in an upwardly direction directly through the space intervals between the surfaces of said balls and the grinding surface of said ring and then through said conduit for the purpose of thereby utilizing the circulating said liquid as a carrier for the material to be ground and reground until pulverized to the desired degree of fineness.

9. In a pulverizing mill,the combination of a stationary upright, housing containing a liquid,

grinding means submerged in said liquid, conv duit means for conveying a flow of said liquid and the material to be pulverized into said housing, an upright funnel element fixedly secured within said housing above said grinding means as to cause the discharge flow of ground mate: rial and fluid to pass upwardly from said grinding means along the outer surface thereof, an hydraulic classifier comprising an open-top channel for receiving said discharge flow, and means for adjustably locating said classifier inwardly of the upper rim of said funnel element, whereby the heavier material in said discharge flow will fall downwardly into the interior of the funnel during its travel from the outer funnel I rim' toward the classifier.

HAROLD v. smmmma. 

